The present invention relates to an enveloping device and a vertical heat-treating apparatus for a semiconductor process system, and particularly to a heat-treating apparatus which is capable of performing processes, such as oxidation, diffusion, and CVD (Chemical Vapor Deposition), in series. The term "semiconductor process" used herein includes various kinds of processes which are performed to manufacture a semiconductor device or a structure having wiring layers, electrodes, and the like to be connected to a semiconductor device, on a target substrate, such as a semiconductor wafer or an LCD (Liquid Crystal Display) substrate, by forming semiconductor layers, insulating layers, and conductive layers in predetermined patterns on the target substrate.
In a process of manufacturing a semiconductor device, various kinds of heat-treating apparatuses are used for subjecting a semiconductor wafer to processes, such as oxidation, diffusion, CVD, and annealing. The heat-treating apparatuses are roughly categorized into two types, i.e., a single-substrate-processing type in which wafers are processed one by one in a process chamber, and a batch-processing type, which is of a horizontal type or a vertical type, in which wafers are processed all together in a process chamber.
For example, a vertical CVD apparatus of the batch-processing type employs a vertically long process chamber for accommodating a boat in which a number of wafers are stacked with a gap therebetween. The process chamber is constituted of a cylindrical reaction tube or process tube made of quartz and a cylindrical manifold made of a metal, which is attached to the bottom of the reaction tube and has a gas inlet and a gas outlet. The manifold is provide with a port at its bottom, through which the wafer boat is loaded and unloaded to and from the reaction tube, while the wafer boat is supported on a metal lid for opening and closing the port. O-rings are used for connecting portions of the parts constituting the process chamber to ensure that the process chamber is highly airtight.
On the other hand, a vertical diffusion or oxidation apparatus of the batch-processing type also employs a vertically long process chamber for accommodating a wafer boat. The process chamber is constituted of a reaction tube made of quartz having a gas inlet and a gas outlet on its side wall. The reaction tube is provide with a port at its bottom, through which the wafer boat is loaded and unloaded to and from the reaction tube, and a quartz lid for opening and closing the port. In other words, the process chamber is entirely made of quartz to ensure that the process chamber is highly heat-resistant and highly corrosion-resistant.
The CVD apparatus described above is capable of handling a process using a high vacuum condition, but does not suit a process using a high temperature or a corrosive gas, because the apparatus employs several O-rings and the metal manifold. On the other hand, the diffusion or oxidation apparatus described above is capable of handling a process using a high temperature or a corrosive gas, but does not suit a process using a high vacuum condition, because the apparatus is not highly airtight.
Accordingly, where processes of oxidation, diffusion, and CVD are to be performed in series in a conventional semiconductor process system, heat-treating apparatuses respectively dedicated to the different processes have to be arranged. In this case, a wafer has to be transferred among the apparatuses for respective processes, thereby entailing a waste of time as well as degradation in the quality of a film formed on the wafer.